Air processor

ABSTRACT

There is described an electrical ion generator for producing large concentrations of ionized molecules in air and utilizing an electrode structure in which one or more electrodes are each positioned inside a sealed dielectric tube filled with an ionizable gas, such as neon. The electrode is connected to one side of a high-frequency, high-voltage source, the other side of the source being connected preferably to another such electrode within a sealed dielectric tube spaced from but parallel to the first tube. Alternatively, one of the electrodes connected to the voltage source may be a conductor in the form of a plate or rod which is at ground potential.

PATENTEDUBT 3 I972 SHEET 1 OF 2 wwwm JJ L 106/75 JU pO/QT l N VEN TORS 0565445 AIR PROCESSOR FIELD OF THE INVENTION This invention relates to air processing devices, and more particularly, to an electrical ion generator having a special electrode structure for introducing gas mechanisms in the atoms and molecules of air to ionize, excite and otherwise activate the processed air.

BACKGROUND OF THE INVENTION Heretofore various methods and apparatus have been devised for processing air to remove dust, pollen, and other particulate matter and reduce chemical impurities which otherwise cause objectionable corro-' sion, odors, skin, nose and eye irritation, and the like. Various types of mechanical filters have been devised for removing particulate matter, but mechanical filtering is'practical only in removing relatively large size particles. Electrical precipitators have been developed for removing smaller size particles. However, both filters and precipitators are effective in removing pollutants only from the air moving through the device. As a result there is a rapid build-up of the materials removed from the air within the device, necessitating special means for collecting and removing the particulate matter from the equipment and to maintain the overall efficiency. Electrical arc discharge devices have been proposed also for processing air, which generate ozone and some ionization of air. This has a sterilizing efi'ect on the air by killing bacteria and other microorganisms, and also has the effect of oxidizing certain chemical substances. However, a large concentration of ozone is objectionable because of its undesirable odor and because of its irritating effect on the eyes and mucous membrane areas of the human body. Moreover, arc discharged devices require continuous maintenance. Electrodes have to be frequently changed because the arc discharge produces pitting and burning of the electrodes due in part to overheating by the arc in the presence of large concentrations of ozone.

SUMMARY OF THE INVENTION The present invention is directed to an improved air processor which utilizes activation means whose origin is concentrated primarily in a fully enclosed region. Thus the necessity of having exposed electrodes which are subject to corrosion and deterioration associated with conventional arc discharge generators, is avoided. Excitation and ionization of molecules in the air is achieved without necessarily producing an arc discharge within the air itself, thus greatly minimizing the amount of ozone produced relative to the concentration of ionized air molecules produced. This is accomplished, in brief, by providing an electrode structure in combination with a high-frequency high-voltage source in which gas mechanisms such as excitation, ionization, arcing, sparking, and corona discharge, are produced in a sealed environment. By release of photons and/or electrical discharge, gas mechanisms such as excitation and ionization and ozone generation are induced in the air surrounding the sealed environment, this air being circulated and mixed with surrounding air before effectively processing large volumes of air.

In brief, the air-processing apparatus of the present invention includes one or more electrodes, each of which is positioned inside a sealed dielectric tube filled with an ionizable gas such as neon. These electrodes are arranged in pairs with one electrode of each pair being connected to opposite terminals of a high-voltage, high-frequency generating source. The electrodes are arranged in adjacent parallel configuration to provide elongated air gaps between the dielectric tubes. Air is continuously moved through the spaces between the electrodes where the molecules of air are ionized or excited by the combination of the high-frequency voltage and the induced effects of the gas mechanisms within the tube. By this arrangement, the molecules of the air circulated through the spaces between the tubes become highly ionized with a minimum of ozone generation.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, reference should be made to the accompanying drawings wherein:

FIG. 1 is a diagrammatic showing of the preferred embodiment of the electrode structure of the present invention;

FIG. 2 is a schematic showing of an air processor utilizing the preferred electrode structure; and

FIGS. 3, 4, 5, 6, and 7 are diagrammatic showings of various modified electrode structures.

DETAILED DESCRIPTION Referring to the preferred embodiment of FIG. 1, the numeral 10 indicates generally a high-frequency, highvoltage source, such as the type described in the copending application, Ser. No. 835,399, filed June 23, 1969, by the same inventors as the present application. The source is capable of providing voltages of the order of 25 to 30 kilovolts with frequencies in the range of 2 to 20 kilohertz or higher.

The electrode structure comprises a plurality of elongated tubes, indicated generally at 12. The tubes 12 are preferably constructed of glass but may be made of other dielectric material preferably transparent to photons in the visible and ultra-violet range. The tube is filled with a conductive fluid, such as an ionizable inert gas. Neon, for example, is suitable for this purpose since it is readily ionized at pressures of the order of 7 to 10 psi. Each neon tube includes a conductive electrode element 14 extending inside the tube with one or more electrical leads 16 extending through the walls of the tube to provide an external electrical connection. The neon filled tubes are arranged in parallel spaced relationship by mounting them in support members 18 and 20 which may be made of Lucite or other suitable material of strong dielectric properties. Typically, the neon tubes are spaced apart 0.75 inch. However, this spacing is not critical and may be varied depending upon the voltages used and the environmental conditions in which the generator operates.

In one embodiment of an air processor, the tubes are arranged in pairs with one tube of each pair having the electrode connected to one terminal of the high-voltage source 10 and the other tube of the pair connected to the opposite terminal of the high-voltage source 10. A plurality of such pairs of electrodes may be provided to form an array. Tube arrays utilizing up to 18 tubes have provided excellent results. i

As shown in FIG. 2, the tubes of the array need not necessarily be arranged in a plane. The tubes may be arranged in'a curve or angle to reduce the projected area of the array without reducing the number of tubes. Air is passed through the spaces between the tubes by a suitable fan 22. In the region of the tubes the air is excited and ionized. By varying the circuit parameters, such as increasing the high voltage to create a strong arc discharge between pairs of tubes, ozone can be generated as well. Where it is preferred to generate primarily ions in the processed air, the high voltage can be decreased to suppress arcing or a filter 24 may be provided downstream of the neon tubes through which the air passes. The filter causes the unstable molecules of ozone to decompose back into molecules of oxygen, but does not appreciably affect the density of excited or ionized molecules in the air. The same effect of reducing the ozone content may be accomplished by heating the air, which also helps decompose the ozone without affecting the amount of excitation or ionization present.

While the use of gas-filled tubes enclosing both sets of electrodes connected to the high voltage source is preferred, various other configurations using gas-filled tubes for only one of the electrodes have shown improved results over conventional electrode structures. FIG. 3, for example, shows an arrangement in which a single neon tube 40 is used with one electrode, with a concentric metal tube 42 forming the other electrode. Air is circulated through the tube 42 to expose it to the gas mechanisms occurring between the neon tube 40 and the outer metal tube 42. The high-voltage source is connected across the two electrodes.

In the arrangement of FIG. 4, the metal tube electrode 42 is replaced by a group of metal rods 44 which are spaced equidistant from the neon tube 40. In the arrangement of FIG. 4, the air can be moved through the space between the rods 44 and need not be moved lengthwise of the neon tube, as in the arrangement of FIG. 3.

FIG. 5 shows a further modification in which the center electrode is in the form of a wire brush 46. The other electrode consists of a group of neon tubes 48 spaced in a concentric ring about the brush 46. The neon tubes are all electrically joined to one terminal of the high-voltage source 10, while the brush 46 is connected to the other terminal of the high-voltage source 10.

FIG. 6 shows a configuration in which the cylindrical metal tube 42 of FIG. 3 is replaced by one or more flat metal plates 43. One terminal of the high-voltage supply is electrically connected to the neon tubes. The other terminal of the high-voltage supply is electrically connected to the metal plates. The plates are connected to ground potential to provide safe operation.

FIG. 7 shows a further modification in which one or more metal plates 43 are electrically connected to alternate tubes of the array and one terminal of the highvoltage supply. The remaining metal plates and the remaining tubes are electrically connected to the other terminal of the high-voltage supply.

From the above description it will be recognized that the present invention provides an improved electrode structure for an air processor in which one or both electrodes have gas-filled tubes surrounding the electrodes. While the production of ozone can be limited by maintaining the high-voltage supply at a level below which arc discharge takes place between electrodes, where ozone is not a problem or is eliminated by filtering or the like, ionization efficiency can be improved by raising the voltage above the point where arcing takes place. In such case, the gas-filled tube acts as part of the electrode, providing improved electrode life, since the arc discharge tends to migrate from point-to-point along the length of the tubes. The dielectric material of the tubes is not subject to the burning and corrosion that metal electrodes incur in the presence of an arc.

Moreover, the continuous movement of the arc prevents hot spots which could cause localized destruction, Even if hot spots occur, the insulating material from which the tube is made may be ablated away, thereby eliminating a minor imperfection in the tube material which causes the hot spot to develop. Thus the ablative action tends to equalize the distance between the tubes and eliminate the concentration of the arc at any one point. g

While the ionization and other gas mechanisms which take place in the gas-filled tube are important in increasing the amount of ionization taking place in the air outside the tube, where arc-type discharge operation is used, it is possible to fillthe tubes with a dielectric liquid capable of conducting electricity, such as ordinary tap water, which normally contains enough dissolved salts to provide conductivity. Such a fluid-filled tube still has the advantage that the electrode is protected from the arc, providing greatly increased longevity of the electrode structure.

By providing an air-processing system which permits higher concentrations of ionized molecules in the air relative to the amount of ozone produced, the air processor finds particular use in the dissipation of electrostatic charge which can be such a problem in processing of photographic film, for example. Thus the production of high concentrations of ionized molecules, which are then circulated through a room filled with photographic film that is being processed, quickly dissipates any electrostatic charge which causes film strips to adhere to each other and to attract dust particles floating in the air. Not only is the electrostatic charge dissipated, but the dust particles become attracted to each other and thus build up their size until they are sufficiently heavy to drop out of the air. This latter effect has particular application to clearing dustladen atmospheres such as are encountered in certain industrial applications, and in the housing of poultry and the like.

What is claimed is:

1. An electrode structure for an ion generator comprising an array of two or more parallel elongated sealed tubes, conductive fluid in the tubes, an electrical conductor extending into the tubes, conductive means connecting the conductor of alternate tubes of the array to one terminal of a voltage source, and conductive means connecting the conductors of the remaining tubes to the other terminal of the voltage source.

2. Apparatus as defined in claim 1 wherein the tubes are filled with an ionizable gas.

3. Apparatus as defined in claim 1 wherein the tubes are filled with an electrolyte solution.

4. Apparatus as defined in claim 1 further including means for moving air past the tubes in the array.

5. Apparatus as defined in claim 1 further comprising a pair of parallel conductive plates positioned on either side of said tubes, the plates being spaced from the tubes to permit air to pass freely between the tubes and the plates, conductive means connecting one plate to the one terminal of the voltage source, and conductive means connecting the other plate to the other terminal of the voltage source.

6. Apparatus for processing air comprising a pair of spaced apart parallel conductive plates, spacer means of nonconductive material securing the plates in fixed relationship and positioned along opposite edges of the plates, whereby air can pass freely between the plates, a plurality of elongated sealed dielectric tubes supported by said spacer means and projecting into the space between the conductive plates, each tube having an electrical conductor extending into the tube and having a conductive fluid in the tube, and a high voltage alternating current source connected between at least one of the plates and the electrical conductors of said tubes. 

1. An electrode structure for an ion generator comprising an array of two or more parallel elongated sealed tubes, conductive fluid in the tubes, an electrical conductor extending into the tubes, conductive means connecting the conductor of alternate tubes of the array to one terminal of a voltage source, and conductive means connecting the conductors of the remaining tubes to the other terminal of the voltage source.
 2. Apparatus as defined in claim 1 wherein the tubes are filled with an ionizable gas.
 3. Apparatus as defined in claim 1 wherein the tubes are filled with an electrolyte solution.
 4. Apparatus as defined in claim 1 further including means for moving air past the tubes in the array.
 5. Apparatus as defined in claim 1 further comprising a pair of parallel conductive plates positioned on either side of said tubes, the plates being spaced from the tubes to permit air to pass freely between the tubes and the plates, conductive means connecting one plate to the one terminal of the voltage source, and conductive means connecting the other plate to the other terminal of the voltage source.
 6. Apparatus for processing air comprising a pair of spaced apart parallel conductive plates, spacer means of nonconductive material securing the plates in fixed relationship and positioned along opposite edges of the plates, whereby air can pass freely between the plates, a plurality of elongated sealed dielectric tubes supported by said spacer means and projecting into the space between the conductive plates, each tube having an electrical conductor extending into the tube and having a conductive fluid in the tube, and a high voltage alternating current source connected between at least one of the plates and the electrical conductors of said tubes. 